The present invention relates to a process for connecting two fabric pieces and also to a seam of two fabric pieces.
For the purpose of producing floating bodies that are capable of being filled with air—for example, RIBs (Rigid Inflatable Boats), inflatable dinghies with a rigid keel, motorisable inflatable dinghies or generally larger inflatable dinghies of varying type—several fabric pieces are assembled to form the floating body. In this connection it is particularly important that the fabric pieces are firmly and tightly connected to one another at the joints, and that the seam exhibits the same mechanical strength as the fabric pieces. By way of material for the floating bodies, use is made of fabric that has been provided with a coating. Depending on the differing possible coatings that are used, differing manufacturing techniques are used for the purpose of connecting the fabric pieces.
A first possibility is the use of a fabric that has been provided with polyvinyl chloride (PVC), polyurethane or another thermoplastic coating. Connection of the fabric pieces is effected in this case by welding, which is undertaken by means of high frequency (HF) or by means of heat and, where appropriate, pressure. A second possibility is the use of fabric with unvulcanised elastomer coatings, in which case the fabric pieces are then fully connected to one another by means of vulcanisation of the elastomer coating. A third possibility consists in the use of fabric with an already vulcanised elastomer coating which is cold-bonded.
FIG. 1a shows a first possibility of how two fabric pieces can be connected to one another by means of the aforementioned manufacturing techniques and coatings. In this case a first fabric piece 1 is arranged overlapping with a second fabric piece 2. On the surfaces 7 of the fabric pieces 1, 2 there is located—depending upon the manufacturing technique being used—a thermoplastic coating, an unvulcanised elastomer coating, or a vulcanised elastomer coating. By means of the aforementioned processes, the two fabric pieces 1, 2 are connected to one another at the place of overlap. In the case of the use of a fabric with a vulcanised elastomer coating, adhesive 4 is applied at the place of overlap of the fabric pieces 1, 2.
FIG. 1b shows another possibility of the connection of two fabric pieces. In this case a first fabric piece 1 and a second fabric piece 2 are connected to one another on a part of the fabric surface, so that the two fabric pieces represent a T-shaped connection. On the side at which the fabric pieces 1, 2 gape apart, a seam tape 5 is provided. This seam tape 5 serves primarily for preventing an opening or gaping of the fabric pieces 1, 2. In general, seam tapes serve for protecting the seam and/or as a force-transmission element. Inseam tapes serve, in particular, for ensuring that air does not penetrate into the fibrils of the fabric and is consequently able, in effect, to find a channel to the outside. Outseam tapes serve, in particular, for ensuring that water does not penetrate from outside into the fibrils of the fabric as a result of wicking, consequently changing the adhesion of the coating adversely in the course of time. The surfaces 7 of the fabric pieces 1, 2 and the surface 7 of the seam tape 5 are provided with a thermoplastic, a vulcanised or an unvulcanised elastomer coating, so that—depending upon the manufacturing technique—the fabric pieces 1, 2 and the seam tape 5 can be connected to one another. In the case of the use of a fabric with a vulcanised elastomer coating, adhesive 4 may have been applied at the points of contact between the fabric pieces 1, 2 and the seam tape 5.
A disadvantageous aspect of such a seam is the fact that it can only be repaired with difficulty in the event of damage, and it is not aesthetic.
FIG. 2 shows another possibility of the connection of two fabric pieces using the methods stated above. In this case a first fabric piece 1 is arranged overlapping with a second fabric piece 2. On both sides of the places of overlap a seam tape 5, 6 is provided. Connection of the two fabric pieces 1, 2 and also of the seam tapes 5, 6 is effected in this case in a manner depending on the coating that is used on the surfaces 7. In the case of the use of a fabric with a vulcanised elastomer coating, adhesive 4 is applied onto the points of contact between the fabric pieces 1, 2 and the seam tapes 5, 6.
FIGS. 3a and 3b show the connection of two fabric pieces 1, 2 using only one seam tape 5, 6, respectively.
FIG. 4 shows the connection of two fabric pieces 1, 2 in a head seam. In this case the fabric pieces 1, 2 are arranged in such a way that they abut at their edges. On each of the two sides of the fabric pieces 1, 2 a seam tape 5 and 6, respectively, is provided. The fabric pieces 1, 2 and seam tapes 5, 6 are provided on their surfaces 7 with a coating, so that by means of the aforementioned processes the fabric pieces 1, 2 can be connected to the seam tapes 5, 6.
However, the processes that have been described exhibit various disadvantages. Fabric that is provided with a thermoplastic coating does not exhibit the ageing characteristics and resistance to weathering of fabric that exhibits an elastomer coating. In particular, polyvinyl chloride (PVC) easily becomes fragile and brittle as a result of the loss of the plasticisers. Polyurethane and other thermoplastics do not exhibit any colour stability or resistance to hydrolysis.
A disadvantageous aspect in the case of fabric with an unvulcanised elastomer coating is a very elaborate production process. Shaping is effected by applying the out of unvulcanised elastomeric-coated fabric onto predetermined moulds and by subsequent vulcanisation, as a result of which, on account of the use of certain predetermined shapes, no modification or personalisation of the shape is possible. Another disadvantage of fabric with an unvulcanised elastomer coating is that the fabric is very sensitive and can easily be damaged.
Fabric with a vulcanised elastomer coating is connected together by bonding. For this purpose, the surface to be bonded have to be roughened and coated with solvent-containing adhesive. This manufacture is very time-consuming and unecological, since the solvent has to evaporate completely prior to closure of the seam.